title: Phylogenetic relationships of North American western chubs of the genus Gila (Cyprinidae, Teleostei), with emphasis on southern species.
abstract: Species of Gila comprise a heterogeneous and widespread group of freshwater fishes inhabiting drainage systems of western North America. The classification of species of Gila and relatives has been complicated and sometimes compromised by differences in body shapes, sizes, habitats, variable taxonomic placement by early taxonomists, and instances of hypothesized hybridization. While most attention on Gila has focused on hybridization in USA, little is actually know about their intra and intergeneric relationships. We present a molecular phylogeny using 173 specimens for all 19 recognized species of Gila, covering their entire distributions in 31 major drainages. Using one mitochondrial and three nuclear genes, specimens of Gila were analyzed with 10 other North American genera that comprise the Revised Western Clade. All analyses identified most species of Gila in a lineage that always included the monotypic genera Moapa and Acrocheilus, and we recommend the synonymy of both genera with Gila. The composition of this Gila lineage varied depending on the genes analyzed. Within the Gila lineage, similar morphotypes (forms adapted to fast currents vs. general forms) were not resolved as closest relatives. Analyses of mitochondrial DNA resolved all species of Gila from Mexico in reciprocally monophyletic clades except G. modesta. Most species of Gila in the USA were nested in 3 major clades, potentially indicating some level of historic or contemporary interspecific hybridization. Herein, we redefine the ranges for all species of Gila in Mexico. Relevant taxonomic and conservation implications stemming from the results are discussed.
authors.affiliation: Department of Biology, Saint Louis University, 3507 Laclede Avenue, St. Louis, MO 63103, USA. Electronic address: susana.schonhuth@gmail.com.
authors.forename: Susana
authors.initials: S
authors.lastname: Schönhuth
authors.forename: Anabel
authors.initials: A
authors.lastname: Perdices
authors.forename: Lourdes
authors.initials: L
authors.lastname: Lozano-Vilano
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: García-de-León
authors.forename: Héctor
authors.initials: H
authors.lastname: Espinosa
authors.forename: Richard L
authors.initials: RL
authors.lastname: Mayden
mesh_terms: D000818:Animals; D003530:Cyprinidae / Q000145:classification / Q000235:genetics*; D004272:DNA, Mitochondrial / Q000235:genetics; D019143:Evolution, Molecular; D006824:Hybridization, Genetic; D008800:Mexico; D008928:Mitochondria / Q000235:genetics; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D015206:Southwestern United States
chemical_list: D004272:DNA, Mitochondrial
keywords: Arid–semiarid regions; Gila; Hybrids; Moapa; Western Clade; Western cyprinids